How to use the instaloader.Profile.from_username function in instaloader

def test_private_profile_paging(self):
        self.post_paging_test(instaloader.Profile.from_username(self.L.context, PRIVATE_PROFILE).get_posts())

def test_public_profile_paging(self):
        self.post_paging_test(instaloader.Profile.from_username(self.L.context, PUBLIC_PROFILE).get_posts())

def test_saved_paging(self):
        for count, post in enumerate(instaloader.Profile.from_username(self.L.context, OWN_USERNAME).get_saved_posts()):
            print(post)
            if count == PAGING_MAX_COUNT:
                break

def test_public_profile_tagged_paging(self):
        for post in islice(instaloader.Profile.from_username(self.L.context, PUBLIC_PROFILE).get_tagged_posts(),
                           PAGING_MAX_COUNT):
            print(post)

def test_get_followees(self):
        profile = instaloader.Profile.from_username(self.L.context, OWN_USERNAME)
        for f in profile.get_followees():
            print(f.username)

def test_post_from_mediaid(self):
        for post in instaloader.Profile.from_username(self.L.context, PUBLIC_PROFILE).get_posts():
            post2 = instaloader.Post.from_mediaid(self.L.context, post.mediaid)
            self.assertEqual(post, post2)
            break

def test_public_profile_igtv(self):
        for post in islice(instaloader.Profile.from_username(self.L.context, PUBLIC_PROFILE_WITH_IGTV).get_igtv_posts(),
                           PAGING_MAX_COUNT):
            print(post)

def test_get_similar_accounts(self):
        profile = instaloader.Profile.from_username(self.L.context, OWN_USERNAME)
        for f in profile.get_similar_accounts():
            print(f.username)

def test_get_followers(self):
        profile = instaloader.Profile.from_username(self.L.context, OWN_USERNAME)
        for f in profile.get_followers():
            print(f.username)